Determine the effects of testosterone on the expression of human TXA2 receptors. a. Determine the effects of testosterone administration to normal male volunteers on platelet TXA2 receptor affinity and density and ex-vivo platelet aggregation responses. b. Determine the effects of testosterone administration to normal male volunteers on vascular reactivity to TXA2. c. Determine the effects of surgical or chemical castration on platelet TXA2 affinity and density and TXA2 mimetic induced platelet aggregation in patients with prostatic carcinoma. d. Determine the effects of puberty on human platelet TXA2 receptor density and affinity in normal male and female volunteers e. Determine the density of platelet TXA2 receptors and aggregation responses to TXA2 mimetics and ADP in pre- and post- menopausal females and age matched post-pubescent males.